[Biofilms and public health].

Micro-organisms do not always exist in planctonic forms (single cells or small groups). To survive, especially in limiting media, they may adhere to inert or living surfaces. This enables them to multiply within a community protected by an extracellular matrix, thus forming a biofilm which protects them from antimicrobials. Biofilms have many potential consequences for public health. Some are positive, such as the commensal biofilms that protect against pathogenic bacteria, while environmental biofilms may be a source of outbreaks of respiratory or gastrointestinal diseases or infections associated with implanted medical devices. Respiratory tract infection can be caused by aerosols of fragmented biofilms growing in warm humid conditions (air cooling towers, hot springs, showers, etc.). Digestive tract infection can arise from biofilms formed during food manufacturing or packaging processes. Colonized implanted medical devices can lead to sepsis. This article examines the role of central venous catheters, taking into account the surgical site. In vivo studies show that the source of catheter infection may be exogenous or endogenous, while in vitro studies of biofilms show that ablation of the device is the best solution. Prevention is difficult, as biofilm formation is multifactorial. Physical and biological knowledge of biofilms may help to limit their formation and growth.